The invention relates to lockable lids or covers adapted to be threadedly engaged on the outer end of a filler tube associated with a vehicle gas cap.
In known designs of this type, an inner hollow shell has a threaded front portion for engagement with the filler tube. Such inner shell is received within, and is normally coaxially rotatable with respect to, an outer shell. A key-operated cylindrical tumbler is arranged between the inner and outer shells, and is provided with facilities for coupling the inner and outer shells for joint rotation when the key is operated. At such time, a manual rotation of the outer shell will cause the cap assembly to be unscrewed from the filler tube.
In general, the key-operated cylindrical portion is sealed within the outer shell, while the selective coupling beween the inner and outer shells is effected by means of a pin or axle also secured to the outer shell and adapted to fit within a circular aperture of the inner shell.
Such existing designs have been found to be relatively clumsy and unreliable, as well as difficult to physically remove from the filler cap when the key is operated.